1. Field of Invention
The field of the present invention relates in general to current controllers and more particularly to current controllers in digital modems.
2. Description of the Related Art
Current controllers are a basic building block of electrical circuits serving as: digital to analog converters, programmable attenuators, programmable gain controls, signal/noise cancellers, balancing circuits, digital potentiometers and data converters or quantizers for example. They are often implemented as switchable resistor or attenuator arrays in an integrated circuit. The required resistors and switches occupy significant amount of chip area and introduce other non-idealities such as distortions and stray capacitance. Some implementations also produce redundant states. It is often hard to find a number of available states that is neither too large nor too small for the application.
What is needed is a current controller with reduced distortion and scale.